绿手指
首页
动态
文章
百科
花园
设置
简体中文
已关注
+
关注
花园 (6)
动态 (3585)
Dummer. ゛☀
2017年09月16日
Dummer. ゛☀
Numerous species of leafhoppers and planthoppers are found in Missouri, and many of them have a broad host list (for example, the potato leafhopper, Empoasca fabae, has over 100 host plants). They feed on foliage and shoots of many different plant species by piercing the plant cells and sucking out the contents. The damage that results from feeding depends on the host plant and the specific hopper. Only a few species of hoppers transmit pathogens such as those that cause curly top virus and aster yellows. Adult hoppers are excellent short-distance jumpers when disturbed, and they can be pests when found in high numbers.
Symptoms and Diagnosis Hoppers are agile insects that can move with equal ease either forwards, backwards, or sideways like a crab. The crab-like motion distinguishes hoppers from most other insects. In addition, they can hop to escape danger or to move to another host plant. Feeding damage from some species causes small white spots (stippling) to appear on the upper leaf surface, usually beginning near the leaf midrib. Stippled areas can unite into larger whitish blotches on mature leaves. With some plants, feeding damage causes a drying and yellowing (or browning) of leaf margins, and possibly the whole leaf. Some leafhopper species cause curling or stunting of terminal leaves with their feeding. Another sign of feeding is the presence of tiny varnish-like spots of excrement on the underside of leaves. Also, check under leaves for white, papery cast skins that remain from the molting process.
The lacebug is another insect that causes stippling from feeding and leaves dark droplets of varnish-like excrement on the underside of leaves. Distinguishing lacebugs from leafhoppers is easy: Lacebugs have a lacy pattern on their upper side, they don't jump or run sideways, and they are about half as broad as they are long. Yet another pest that can cause stippling is the spider mite. Check under leaves for the webbing left by spider mites (leafhoppers don't leave webbing).
Life Cycle Adults of most species of leafhopper range between 1/8 to 1/4 inch long. They are slender and frequently have an angular, pointed head. Coloration depends on species, but generally leafhoppers are shades of green, brown, or yellow and are often mottled. Nymphs (immatures) look similar to the adults except that the nymphs are smaller and don't have wings. Nymphs typically feed on the underside of leaves, where the humidity is higher and they are more protected from predators. Leafhoppers have several generations each year. Some species migrate south in winter and return north with late spring weather.
Integrated Pest Management Strategies 1. Live with the pests. Because of their mobility and abundance, leafhoppers are not easy to control. However, leafhoppers are seldom present in large enough numbers to seriously injure plants. In addition, leafhoppers have many natural enemies, including lady beetles, lacewings, damsel bugs, and spiders. They are also subject to diseases and parasites that help keep their numbers down under most conditions. 2. Use row covers. Floating row covers or netting can be placed over plants early in summer to exclude leafhoppers. Remove row covers when the plants begin to flower. 3. Monitor with sticky traps. Many leafhoppers are attracted to yellow sticky traps which should be placed close to the foliage of the crop. Populations can be monitored with sticky traps and low populations can be managed using these traps.
4. Apply insecticidal soap. Insecticidal soap can control leafhoppers if applied when the insects are small. The immature leafhoppers are usually found on the underside of leaves so be sure to spray there also. 5. Apply insecticides. Other insecticides available for leafhopper control include botanical pyrethrins, carbaryl (Sevin), malathion, bifenthrin, cyfluthrin, bendiocarb (Turcam, Closure), disulfoton (Disyston), and acephate (Orthene). In general, these are most effective on the immature leafhoppers because they can't escape as well as the adults and are typically more susceptible to chemicals.
0
0
文章
Dummer. ゛☀
2017年09月16日
Dummer. ゛☀
Leaf cutter bees (Megachile rotundata) are small native bees about ¼ inch long, robust and dark grey with a pollen brush on the underside of the abdomen. They are beneficial for the most part and only cause minor damage to ornamentals such as rose and ash by cutting half moon-shaped disks from the leaves. They are not aggressive but can give a mild sting if handled. They are important plant pollinators.
Symptoms and Diagnosis The most characteristic symptom of leaf cutter bees are the half-moon shaped holes they make on the edges of leaves as they remove disks of leaf tissue to take back to form nest cells. A leaf may have a single disk removed or several.
Life cycle Leafcutter bees are solitary bees. They do not form colonies. Females emerge in late spring, mate and form new nests in soft, rotten wood, the pith area of plants, or other existing holes of the correct size. They line the nest with the leaf fragments they collect, provision each cell with a mixture of nectar and pollen, lay an egg and seal the cell. Finished nests may contain a dozen cells or more. The young bees develop and remain in the cell overwintering as a full-grown larvae. There is only one generation a year.
Integrated Pest Management Strategies 1. Prevention. Eliminate breeding sites. Look for rotting boards with sawdust pushed out of excavated tunnels or thick stemmed plants with hollowed openings. 2. Mechanical control. Cover susceptible plants with cheesecloth or other loose netting during periods when leafcutter bees are most active (in late summer). To prevent leafcutter bees from tunneling into rose canes, seal exposed pith as canes are pruned. Place a thumb tack, bit of sealing wax or white glue on the opening.
3. Chemical controls. Insecticides are ineffective for preventing leaf cutting. Remember, leafcutter bees are native, beneficial bees, important as pollinators.
0
0
文章
Dummer. ゛☀
2017年09月16日
Dummer. ゛☀
Japanese beetles are 3/8" (8-11 mm) long and ¼" (5-7 mm) wide, brilliant metallic green insects with copper-brown wings whose hard body makes them unpalatable to many predators, including birds. To distinguish them from other metallic green or copper-colored beetles, the diagnostic sign is a row of 5 small tufts of white hairs under the wing covers on each side and a 6th pair at the tip of the abdomen. The larvae, called grubs, are grayish-white with a dark brown head. They are C-shaped when disturbed. The 1st instar (stage of an insect or arthropod between molts) is 1/16” (1.5 mm) long and the 3rd instar is 1¼” (32mm) long. They are found in the soil where they feed on the tender roots of vegetables, lawn grasses, and other plants.
Life Cycle Japanese beetles overwinter as a partially grown grub in the soil below the frost line. The grubs resume feeding on grass roots in the spring, and then pupate near the soil surface. Adults emerge between May and July, depending on their geographic location . Adults live 30-45 days and feed, usually in groups, first on low-growing plants and then on tree leaves, working from the top of the plants downward. After feeding and mating, each female lays 1-5 eggs at a time before again feeding and mating until a total of 40-60 eggs are laid 2-4” under the soil surface in grassy areas. Most are laid by mid-August. The eggs hatch after 8-14 days, and the young grubs feed on fine grass roots until cold weather drives them below the frost line. Most are in the 3rd instar by this time. In spring the grubs come to the surface, continuing their development and forming a pupa in an earthen cell 1-3" deep in the soil.
Japanese beetle adults are active for about 6 weeks in the summer. Since adult beetle damage is primarily aesthetic, control is not essential for survival of ornamental plants. Because they are strong fliers and frequently move about, by season’s end, adults are capable of having traveled many miles from where they lived as grubs. As a result, local beetle control does not insure less grub damage to lawns. Likewise, local grub control will not necessarily prevent adult damage to garden plants. Integrated Pest Management Strategies: 1. Hand-pick adult beetles. If only a few adults are present, shake plants early in the morning (~ 7 a.m.) when they are sluggish. They should be collected and dropped into a container of soapy water. Any beetles or damaged leaves will attract more insects and should be removed..
2. Pheromone traps. Research has found that pheromone traps attract many more beetles than they catch and probably do more harm than good to plants in the beetles’ flight path and near the traps. Their use is not recommended. 3. Use insecticides if necessary. To control adults, one of two very safe pesticide, pyrethrum or Neem, can be applied in two applications, 3 to 4 days apart, to control the problem. If something stronger is needed, carbaryl (Sevin) may be used (every 5-10 days during heavy infestation) with monitoring for mites or aphids, in which case acephate (Orthene; more toxic) or malathion should be used. Other insecticides include Turcam, Closure (bendiocarb), permethrin, and synthetic pyrethroids. With any insecticide, efficacy will be decreased if there is heavy rainfall shortly after application of the chemical.
To control grubs present in damaging numbers, newer chemicals, Merit (imidacloprid) and MACH2 (halofenozide), applied in June and July 20 days before anticipated Japanese beetle adult egg-laying activity, have enough residual to kill new grubs coming to the soil surface to feed in late July through August. It is important to apply evenly over all the ground and to water in well. These chemicals will also be effective on other grub species when applied at the appropriate times. 4. Biological controls. The hard body of the beetle makes them unpalatable to many predators, such as birds. However, toads, moles, shrews, and skunks are known to feed on the beetles. To control grubs, bacterial milky spore disease (Paenibacillus popillae, formerly known as Bacillus popillae) can be applied as a dust for Japanese beetle grub control and must be ingested by the grub to be effective. Once inside the digestive tract; spores reproduce within the grub, eventually turning it an opaque milky white before killing it. Spores then disperse into the surrounding soil and can persist for many years, but do not spread until live hosts are present. The more grubs, the faster it spreads. Milky spore infects only Japanese beetle grubs and has no effect on beneficial organisms. Its efficacy is questionable and the spore count has to build up for 2-3 years, during which time no insecticides may be used. More research needs to be done.
Other biological controls are parasitic nematodes that need to be applied when the grubs are small, with irrigation before and after application. Species of Heterorhabditis are said to be more effective than strains of Steinernema carpocapsae. 5. Use trap crops. When practical, crops which are highly favored by Japanese beetles can be used to draw the adults away from other crops. Trap crops include: borage, white geraniums, grape vines, evening primroses, and zinnias. The beetles can be collected or killed on the trap crops. This method provides early detection and can limit the amount of spray needed to control the insects.
6. Select resistant plants. Among trees and shrubs are: ash, dogwood, American elder, shagbark hickory, holly, red and silver maple, oaks, pear, white poplar, sweet gum, and tulip tree; euonymus and common lilac. Avoid planting the most susceptible plants: roses, grapes, and rose of Sharon; apple and crabapple, mountain ash, grey birch, American and horse chestnut, elm, linden, Japanese and Norway maple, London plane tree, Lombardy poplar, Prunus (cherry, etc.), sassafras, and black walnut.
0
0
文章
Dummer. ゛☀
2017年09月16日
Dummer. ゛☀
The iris borer causes more damage to iris plants than any other insect. Feeding of the borer larva opens the rhizome to attack by soft rot that can quickly turn rhizomes into foul-smelling mush. A healthy bed of iris can be destroyed quickly.
Symptoms and Diagnosis Damage is typified by dark streaks, water-soaked areas, and ragged edges on young leaves in May and June, caused by feeding of the young larvae. As the larvae feed, they move down into the rhizome where they continue feeding. Soft rot can set in, causing leaves to yellow and fall over and rhizomes may become soft and foul-smelling. Cutting open the rhizome will reveal the borer, a 1- to 2- inch, fat-bodied, pink larva with a brown head.
Life Cycle Adult moths emerge from the soil in August and September, mate, and deposit eggs on dead iris leaves. The crevices of dried and crinkled leaves or rolled leaf areas make a good place to lay their eggs. The base of leaves and other plant debris is the wintering place of the eggs. Eggs are laid in groups of 3–5 or more; a single female moth may deposit 1000 eggs before dying. Moths are typical millers— dark gray to brown, with a wingspan of about 2 inches. There is only one generation per year.
The eggs overwinter in the plant material and hatch in April or early May as the new iris leaves are expanding. The small, young larvae crawl up onto the new iris leaves and make tiny pinpoint holes as they enter. Once the larvae enter the foliage, they act as leafminers, tunneling to the base of the leaves throughout the spring. By early to mid-July the larvae reach the soil area and tunnel into the rhizomes.
In the rhizome, the larvae grow to be 1 to 2 inches in length. In late July to early August, the iris borer larvae move from the rhizomes into the soil to pupate. The pupa is a non-feeding transition stage between the larva and the adult moth. Pupae are dark brown to black and are usually found in the top 2 inches of soil. After two to three weeks in the pupa stage, the iris borer moth emerges. The adult brown moths emerge in late August and September to mate, lay eggs, and repeat the cycle. Integrated Pest Management Strategies 1. Sanitation. The main key to iris borer prevention is removal and destruction of the previous year’s dead foliage before April 1. This sanitation practice will reduce the problem by destroying overwintering eggs in the residues. This is best done in spring. Peel off the dead foliage down to the rhizome.
2. Inspect bed. If signs of borers are apparent, dig the rhizomes after blooming is completed. Inspect them carefully, cut out damaged ones, and replant. During the spring, inspect the leaves for signs of borers larvae chewing and pinch down the leaves to kill any larvae that may be inside. 3. Precaution. An insecticide containing pyrethrum spread or sprayed around the base of plants in the spring may help in destroying the newly hatched larvae before they have a chance to enter leaves. 4. Insecticides. If the problem is severe, insecticides are available to help combat borers. When iris leaves are 3–4 inches long, begin spraying at two-week intervals, using azadirachtin (Bio-Neem, Margosan-O), endosulfan (Thiodan), or methyl nonyl ketone. These are available under various trade names at nurseries and garden centers. Always follow label directions and read the entire label before using.
5. Replanting. When resetting your iris beds, it is important to trim away damaged or rotted areas on the rhizomes. To eliminate soft rots caused by bacteria, cut off the damaged parts of the rhizomes and dip the undamaged portions in a solution of 1–part household chlorine bleach and 9 parts of water.
0
0
文章
Dummer. ゛☀
2017年09月16日
Dummer. ゛☀
Cyclamen and broad mites are microscopic mites (less than 0.02mm in length) that deform and distort the growing tips of plants that can result in stunted tips, curled leaves and lack of flowering. Cyclamen mites can be a pest of garden strawberry plants and both can be serious pests of a wide range of plants including: African violet, cyclamen, begonia, snapdragon, impatien, gerbera, ivy, and many indoor tropical plants.
Symptoms and Diagnosis The mites are generally not detected until after they have caused significant damage and then only with the aid of a dissecting microscope. Hand lenses are usually not powerful enough to see these small mites. Mites are closely related to spiders and likewise adults have 4 pairs of legs. Larvae, however, have only 3 pairs. Cyclamen mites are usually greenish and transparent and less than 1 mm in size. Their eggs are smooth and more apt to be found hidden in folds of plant tissue. They like to hide in buds or tips of new growth. They avoid light and prefer high humidity and cool (60 degrees F.) temperatures. Their feeding results in stunted growth with leaves generally curling upward. Leaves become stiffened and brittle (black in the case of delphiniums) and flowers are deformed or reduced.
Broad mites are smaller than cyclamen mites, broader, and are faster moving. Adult females are straw colored. Broad mites have a white stripe down their back, but the easiest way to differentiate the two may be by their eggs. Broad mites eggs have many small white bumps on them and are usually observed in more open locations. Typically adults cause deformed shoots and leaves, which usually curl downward, and reduced flowering. Bronzing or purpling of the leaves commonly occurs on the underside of leaves where the mites feed. Broad mites reproduce most prolifically at temperatures between 70 and 80 degrees F.
Lifecycle Cyclamen mites can complete their lifecycle in only 1 to 3 weeks depending upon conditions. Adults can overwinter out of doors as far north as Canada in protected locations and complete many generations a year. Broad mites can complete their lifecycle in only one week and also have a resting, pupal stage. They can overwinter in greenhouses or on indoor plants but is doubtful they can overwinter out or doors in Missouri. Meaning that each year new infestations out of doors develop from plants that have been overwintered indoors or from infested plants obtained from a nursery or garden center.
Integrated Pest Management 1. Dispose of infested plants. Since these mites can be difficult to control and reproduce rapidly, disposing of infested plants is often wise. 2. Sanitation. Examine newly purchases plant in the spring and reject them if they have curled or deformed tips and shoots that may be signs of mites. 3. Heat treatment. Cyclamen and broad mites are heat sensitive and can be killed if immersed in 110 degree F water for 30 minutes. These temperatures are generally low enough to cause little damage to most plants but water temperature must be maintained properly and the whole plant, pot and all, needs to be immersed. Removing heavily infested shoots first may make this process easier.
4. Treat with miticidal/ insecticidal soap or horticultural oil. To be effective the spray must completely cover the insects so apply liberally and make sure the spray reaches under leaves and into shoot tips where the mites hide. 5. Use chemical sprays. Dicofol (Kelthane) a broad-spectrum miticide can give good control. Follow label instructions.
0
0
文章
Dummer. ゛☀
2017年09月16日
Dummer. ゛☀
Millipedes and centipedes are not insects but distant relatives of lobsters, crayfish and shrimp. They are land dwellers, but they prefer moist areas with high humidity. They carry no diseases to man, animals or plants. They are considered more as nuisances than destructive pests, and are beneficial in the garden.
Millipedes Millipedes, commonly called “thousand-leggers”, have elongated, cylindrical bodies with 25+ pairs of short legs, two pairs per body segment. The legs are held beneath the body and appear to ripple in waves as they move. The head is rounded and projects two short antennae. The body color ranges from light brown to black. Millipedes move slowly and coil up when disturbed or dead. They range in length from a half inch to six inches. They are not venomous but possess glands that produce an irritating, foul-smelling fluid. They feed on decaying vegetable matter. Millipedes migrate in great numbers when it is too hot or too cold, too wet or too dry. They may migrate indoors, but they do not reproduce indoors. They are considered beneficial in the garden because they enrich the soil by breaking down decaying vegetation.
Centipedes Centipedes, commonly called “hundred-leggers”, have elongated, flattened bodies with fewer than 25 pairs of long legs, one pair per segment. The legs project laterally from the body. The head is flattened and projects two long antennae. Just behind the head are the jaws that contain venom glands used to paralyze their prey. Centipedes are predators, feeding on insects and spiders. They move rapidly and never coil up their bodies. They are yellow to brown in color and just over an inch in length. Centipede populations do not increase in great numbers. They occasionally enter homes where they prefer dark, moist areas. The house centipede (Scutigera) does enter homes and may reproduce indoors. Centipedes are considered beneficial in the garden and home because they control insect populations
Life Cycle Millipedes Millipede adults overwinter in the soil. In spring the female lays 20-300 eggs in the soil. The first stage larvae have only three pairs of legs on three body segments. The larvae go through 7—10 development stages and become adults in 2—5 years. Adults live for several years. Centipedes Centipede adults overwinter in secluded, moist places. In spring and summer females lay eggs in damp soil. Some species are born complete and others add segments and legs as they grow. They mature in 2—3 years and live up to six years.
Integrated Pest Management Strategies 1. Control Outdoors. Millipedes and centipedes are considered beneficial outdoors; therefore, encourage their presence. To help prevent them from moving indoors: remove organic matter in contact with the house foundation, minimize watering near building foundations, clean up piles of rocks, leaves, compost and general refuse near the building, and make sure doors and windows fit snugly (caulk crevices). Pesticides can be used to treat the foundation and an adjacent three-foot ground strip with dust or aerosol spray labeled for these organisms. Follow label directions precisely.
2. Control Indoors. Hand pick or vacuum to control individuals. Reduce moisture and remove hiding places, or place sticky traps against walls near entryways. You can also use a pesticides if populations are high or persistent. A contact or aerosol sprays containing pyrethrins or carbaryl can be used. Treat baseboards, cracks and crevices. Follow label directions precisely.
0
0
文章
Dummer. ゛☀
2017年09月16日
Dummer. ゛☀
Caterpillars are the larvae of moths and butterflies, and like their winged metamorphoses, they come in all shapes and sizes. While all species share a common appetite for plant foliage, the good news is that the methods for controlling them are basically the same. Before deciding upon a control method, take the time to identify which caterpillars might eventually become the gorgeous butterflies and lovely nocturnal moths we usually welcome to our gardens. These larvae should be protected, and fortunately, most are colorful and harmless.
Caterpillars inflict damage by eating the foliage and stems of just about any plant in your flower or vegetable garden, as well as your fruit and shade trees. Furthermore, they are voracious eaters, and can defoliate a plant in a short period of time. Telltale symptoms of a caterpillar infestation are holes in leaves and chewed leaf edges, as well as leaves that are rolled up or fastened with silk. If you are able to catch the infestation early on, the best strategy for controlling caterpillars is to handpick them, then crush them or drop them in a pail of soapy water. Make sure you also remove rolled or folded leaves that shelter the caterpillars. (Make sure you wear gloves before handling saddleback caterpillars, as their sting is severe.) To prevent inadvertently killing desirable butterflies- and moths-to-be, use a good field guide such as Peterson First Guide to Caterpillars and pick only those caterpillars which become drab adults.
Cleanup and disposal of garden debris throughout the growing season, followed by a thorough end-of-season cleanup, will help reduce the size of future generations of caterpillars. Furthermore, many insects--such as fireflies, ground beetles, soldier beetles, stink bugs, and tachinid flies-- prey upon or parasitize caterpillars, and will gladly assist you in your quest to keep caterpillar numbers under control. Specific recommendations for flowers. An effective but less selective control for caterpillars is to dust or spray all parts of the leaves on which they are feeding (especially the undersides) with BT (Bacillus thuringiensis). Apply at 3-5 day intervals, reapplying after rain, until caterpillars cease to be a problem. For an infestation that is out of control, spray all sides of the leaves with pyrethrum; usually two applications spaced 3-4 days apart will solve the problem.
Specific recommendations for vegetables. There are some species of caterpillars that are particularly troublesome in the vegetable garden. Cabbage loopers, as their name suggests, are very fond of cabbage (including the Chinese variety), and will also feed on lima and snap beans, broccoli, brussel sprouts, cauliflower, lettuce, parsley, radishes, rutabagas and turnips. They damage crops by chewing small to large ragged holes in the foliage, and by boring into developing heads of cabbage family crops. The best control strategy is to spray plants with BT (Bacillus thuringiensis) every 2 weeks until pests are under control, or until heads begin to form in the case of cabbage family members. Other effective controls are handpicking; spraying plants with liquefied and strained cabbage loopers, or hot pepper spray; and planting trap crops such as celery or amaranth. For serious infestations, spray leaves with pyrethrum.
Another caterpillar that shares the cabbage looper's taste in plants is the imported cabbage worm. Symptoms of infestation include ragged holes in the leaves and bits of green excrement; you will also notice white butterflies skipping about from plant to plant. Like cabbage loopers, imported cabbage worms eventually bore into the developing heads of cabbage family plants, turning them into mush in the process. The most effective strategy for controlling this pest is to use an agricultural fleece or net barrier and a preventive BT (Bacillus thuringiensis) spray early in the season, then to use more BT for later infestations. A thorough fall cleanup is essential to prevent recurring infestations, since these pests overwinter in the soil or on garden litter. After harvesting crops, promptly remove all old plants and overgrown weeds, leaving the soil completely bare, then cultivate soil to a depth of 6-8 inches. Make sure old plants are actively composted or destroyed.
European corn borers are most notorious for boring holes into the stalks and ears of the corn plant, but also damage chard, peppers, potatoes and tomatoes. Squash vine borers affect crops such as cucumbers, muskmelons, pumpkins, squash (summer and winter), and watermelons by burrowing into their vines and causing them to wilt. For more information on these pests, see Caterpillars - Borers and Miners: Specific recommendations for vegetables. Parsleyworms are 2 inches long, and are a brightly colored green with yellow-dotted black bands across each body segment. They give off an odor and project orange horns when they are upset. They will someday become lovely, black swallowtail butterflies, so carefully weigh their aesthetic value against the damage inflicted on your carrots, celery, dill, fennel, parsley and parsnip plants before deciding to destroy them. If you decide the parsleyworms are eating excessively into your harvest, reduce their numbers by handpicking them, or try attracting birds such as northern orioles, barn swallows, bluebirds, chickadees, flycatchers and kinglets into your garden.
The tomato hornworm is a large (3 to 5 inches long), green caterpillar with a horn projecting from its rear; it will eventually become a moth whose diurnal feeding habits and ability to hover have earned it the name of "hummingbird moth." The hornworm chews holes in the leaves of dill, eggplant, pepper, potato and tomato plants, and will sometimes also damage the fruits of the latter three. Check damaged plants for dark colored droppings, and spray them with water; this should cause the hornworms to thrash about and enable you to handpick them more easily. If you notice papery cocoons on their backs, remove but don't destroy the caterpillars: they are already doomed by natural parasites, which should be allowed to reproduce. You can also control hornworms with a Bacillus thuringiensis (BT) spray, or a pyrethrum spray if the infestation gets out of hand.
Specific recommendations for trees. This section will address three pests that primarily affect trees: codling moths, gypsy moths, and tent caterpillars. The larvae of codling moths primarily damage apple, apricot and pear crops, both when they are immature and again when they have ripened. Symptoms of infestation include holes in the fruit skin, tunnels through the fruit, and fecal waste in the core; check also for mounds of excrement around the tunnel entrances and for cocoons in the bark crevices. To control this pest, use a preventive spray of Bacillus thuringiensis (BT) early in the season and light horticultural oil later in the season to get the newly hatched larvae before they bore into the fruit. In addition, set out sticky traps to snare the moths during their emergence times (check with orchard growers in your area).
Gypsy moths are imported pests that primarily affect the eastern United States, and their populations fluctuate between sheer nuisance to plague proportions. Their larvae damage host trees by devouring their leaves, often leaving them (and sometimes entire forests) completely defoliated. When the larvae are young, they chew only around leaf edges; by the time they are an inch long, large holes begin to appear in leaves. In July, the mature caterpillars encase themselves in brown shells to pupate. To control this voracious pest, particularly when its population is waxing, spray trees with Bacillus thuringiensis (BT) every 10 to 14 days from late April to mid-June. In June, wrap trunks of vulnerable trees with a piece of burlap a foot wide, hung about chest high; tie it at the center with heavy twine, letting the top fold over to form a skirt. When caterpillars descend from the tree each morning, they will hide under the fold. In the late afternoon, put on garden gloves and sweep the caterpillars off into a container of detergent and water. To prevent future gypsy moth problems, check for egg clusters on lawn furniture before putting it away in the fall, and stone walls, woodpiles, fences, garages and outbuildings throughout the winter. Destroy egg masses by scraping them into a can of kerosene, gasoline or water, or by burning them. Reduce debris on the ground that can serve as protection for egg masses, larvae and pupae.
Tent caterpillars form large, tent-like, silken nests in the forks of tree branches, and can defoliate their woody hosts if given the chance. Remove the nests and destroy the caterpillars by hand. Spray the tree with Bacillus thuringiensis (BT) as soon as you see the nests begin to reappear, and repeat every 5 to 7 days until the pest is gone.
0
0
文章
Dummer. ゛☀
2017年09月16日
Dummer. ゛☀
Aphids are a very large and diverse group of insects that plague the garden especially during the beginning and end of the growing season. At least 4,000 aphid species have been identified; variations in color, size, and appearance make it impossible to generalize.
Symptoms and Diagnosis Aphid damage may appear as pale yellow spots on leaves, leaves that are curled, puckered, or stunted, and/or distorted blossoms. Look for aphids at the beginning of the growing season. They should be especially abundant on stems and buds where nitrogen concentrations are higher. Aphids multiply more rapidly with high nitrogen levels. Another sign to look for is a sooty black layer on the leaves. Because aphids suck more plant sap than they can use, they exude honeydew onto leaf surfaces. Envied by honeybees and ants, this honeydew substance is very sweet and molds quickly.
Life Cycle Females lay eggs toward the end of the growing season in the bark or bud scales of their favorite plant. When the eggs hatch the following spring, the nymphs are all female and are called "stem mothers". These females will give live birth to daughters without mating. Toward the end of the growing season, males are produced, mating occurs, and the eggs will again overwinter in the plant material.
Integrated Pest Management Strategies 1. Through good horticultural practices, aphids can be minimized. One step is to control the amount of nitrogen added to the garden. By using slowrelease fertilizers such as ammonium or urea-based fertilizers, compost, decomposed manure, fish emulsion, or liquid seaweed, you slow the rate at which the aphids can reproduce. Another step is to prune moderately in winter and early spring, saving the heavy pruning for midgrowing season. This prevents the aphids from destroying fresh growth in early spring. The last step is to encourage a continuum of flowers that will attract the aphids’ natural predators— ladybugs and praying mantis.
2. Try spraying the aphids off the plants with plain water, or remove them by hand with a cloth. 3. Insecticidal soap can be used, but in moderation, as it will kill beneficial insects as well as the aphids. 4. Insecticidal baits that contain boric acid can be used to control the ants, which have a symbiotic relationship with the aphids. The ants protect the aphids and get the honeydew that they ooze in return. Use caution; boric acid is toxic to people and animals. Ant barriers placed at the base of infested plants is another way to discourage ants and allow predators to attack the aphid population.
5. Silica Aerogel/Pyrethrin is a product that will dissolve the cuticle layer on the insect causing it to dehydrate and die. 6. Use chemical insecticides. Pesticides registered for use include carbaryl (Sevin), disulfoton (Disyston), malathion, bifenthrin, imidacloprid, permethrin, petroleum oil, and pyrethrins.
0
0
文章
Dummer. ゛☀
2017年09月16日
Dummer. ゛☀
Frost heaving can cause plants to rise up out of the ground as these hens and chicks (Sempervivum) did. Cold-hardy perennials can be damaged by winter weather. Frost heaving is the usual culprit. Wide temperature fluctuations, with repeated cycles of freezing and thawing, cause the water in the soil to expand and contract. These repeated expansions and contractions push and turn plants and their roots. The result is heaving of the crowns. They are pushed up out of the soil breaking some roots and exposing other roots above soil level. The elevated crowns and roots are exposed to cold temperatures and drying winds. They may be seriously damaged, stunted or killed.
Perennials with shallow root systems (strawberries, heuchera, scabiosa, leucanthemum, galliardia, bergenia) or those that have been planted recently and have not had time to establish adequate root systems are prone to frost heaving. Integrated Pest Management Strategies 1. Controlling frost heaving starts with well drained planting beds. Both surface and subsurface drainage is essential to prevent water from pooling in planted beds. Soggy ground will freeze and thaw repeatedly and susceptible plants will heave. The addition of organic material when the beds are prepared helps loosen soil and promotes good soil drainage.
2. Plant early in the fall. Planting perennials at least 6 weeks before the first autumn frost date gives the plants time to establish adequate root systems to anchor themselves. 3. Mulch. Mulching with organic material (compost, ground leaves, straw, or pine needles) will help moderate soil temperatures reducing heaving of root systems. The mulch should be applied after a hard frost, and at a depth of 4 inches. Excess mulch can lead to soggy ground and rodent infestations. Avoid burying the plant’s crown as the mulch is put down.
4. Monitor the plants. Keep a careful eye on susceptible plants. The mulch can hide an exposed, heaved crown. When a problem is found, cover the exposed roots with a layer of soil and re-apply mulch.
0
0
文章
Dummer. ゛☀
2017年09月16日
Dummer. ゛☀
Newly planted annuals and perennials need careful attention to establish and develop properly. Many factors can result in poor establishment or death. Plants that have failed to establish can often be recognized when you tug on a dead, dying or ailing plant and it comes out of the ground with a root ball much the same as when it was planted having failed to send new roots into the surrounding soil. Here are few of the major points to watch to help your plants become well established after planting.
1. Improper watering. Improper watering is probably the most common reason why a plant dies before it becomes established. Newly planted plants have a small root system, which can dry out very quickly. Be sure and water plants well just after planting and then monitor closely. If the root ball is allowed to dry out the young plant will be severely injured and may never recover. On the other hand, if the root ball is kept too wet, the plant’s roots may rot. Maintaining the correct balance is imperative for the first few weeks to promote healthy root development into the surrounding soil.
2. Plants with small root balls and a lot of foliage can dry out very quickly in hot weather. They may need watering every couple of days when first planted, but the goal should be to extend the time between watering as the plant becomes established. A single severe drying event can kill new transplants! Mulching around young plants can help keep soil moisture more uniform. Keep mulch away from the crown of plants, however, as doing so can encourage crown rots by retaining too much moisture at the base of the plant. Mulch should not touch the crown of the plant. 3. Wrong location. It should be obvious that a plant that needs full sun should not be planted in the shade or vice versa, but still people push the limits. Shade plants grown in too much sun may not establish or just burn up. Sun plants growing in too much shade may lose vigor and eventually die. Plants that need a well-drained soil may also die quickly if planted in wet soils where they are susceptible to root rots.
4. Excess summer heat. Certain plants best adapted to climates with cool summers may not perform well in locations with hot, humid summers. Poor growth, yellowing or bleached foliage, and dieback may all be signs that your plant is suffering from heat stress. 5. Mechanical damage to stems. The stems of young plants can be very vulnerable to damage during planting. Use care when planting so you don't create wounds where fungi or bacteria can enter and rot the crown of the plant.
0
0
文章
98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113
相关用户
茉莉花
茉莉花
来自： Faye
朝阳
绿萝
绿萝
来自： 采元气少女✨
长沙
茉莉花
茉莉花
来自： 小松树快乐
长沙
绿萝
绿萝
来自： 水中月
赣州市
茉莉花
茉莉花
来自： 艺源
广安市
芦荟
芦荟
来自： 采元气少女✨
长沙
茉莉花
茉莉花
来自： 阿罗
南昌
芦荟
芦荟
来自： Bailu_Yuan
北京
白掌
白掌
来自： 韩凯
武汉
绿萝
绿萝
来自： 阿罗
南昌
举报 反馈

您有什么意见或建议，欢迎给我们留言。

请输入内容
提交
取消
设置
VIP
退出登录
关闭
分享

分享好文，绿手指（GFinger）养花助手见证你的成长。

关闭
请前往电脑端操作

请前往电脑端操作

关闭
转发
插入话题
提醒好友
发布
/
提交成功 提交失败 最大图片质量 成功 警告 啊哦！ 出了点小问题 转发成功 举报 转发 显示更多 _zh 文章 求助 动态 刚刚 回复 邀你一起尬聊！ 表情 添加图片 评论 仅支持 .JPG .JPEG .PNG .GIF 图片尺寸不得小于300*300px 最少上传一张图片 请输入内容